Combination centrifugal-turbine pump

ABSTRACT

A centrifugal-turbine pump capable of pumping liquids at or near the boiling point with suction heads not greater than 1 foot having a pump casing with first and second pumping chambers laterally disposed and a drive shaft disposed axially of the pumping chambers. A high-pressure regenerative turbine impeller fixed for rotation with the driving shaft. The second pumping chamber extending angularly about the periphery of the turbine impeller and having a discharge opening radially from the turbine impeller. The casing having a suction entrance for the turbine stage opening laterally from the first pumping channel to the second pumping channel. A centrifugal impeller fixed for rotation within the first channel and with the drive shaft and turbine impeller.

United States Patent [72] lnventor Leonard J. Sieghartner Coal Valley,111. [21] Appl. No. 20,881 [22] Filed Mar. 19, 1970 [45] Patented Oct.19, 1971 [73] Assignee Roy E. Roth Company Rock Island, 111.

[54] COMBINATION CENTRlFUGAL-TURBINE l UMP 6 Claims, 12 Drawing Figs.

[52] US. Cl 415/143, 4l6/176,415/170,415/l 13 51 int. Cl ..F04d 11 00,F04d 29/08 [50] Field of Search 415/143, 113, 215, 219, 213, 170;417/244; 416/176, 177, 179

[56] References Cited UNlTED STATES PATENTS 2,368,530 1/1945 Edwards415/143 2,875,698 3/1959 Roth 415/143 .122 11g Z 5 a 9280 2g 74 .-P Z4 177 v IL 3,154,020 10/1964 Sieghartner 415/113 3,247,797 4/ 1 966Sieghartner 415/143 3,261,297 7/1966 Daniel 415/213 3,385,225 5/1965l-lagemann 415/143 FOREIGN PATENTS 711,791 10/1941 Germany 415/143Primary Examiner-l1enry F. Raduazo Att0rney.1ohnson, Dienner, Emrich,Verbeck & Wagner ABSTRACT: A centrifugal-turbine pump capable of pumpingliquids at or near the boiling point with suction heads not greater than1 foot having a pump casing with first and second pumping chamberslaterally disposed and a drive shaft disposed axially of the pumpingchambers. A high-pressure regenerative turbine impeller fixed forrotation with the driving shaft. The second pumping chamber extendingangularly about the periphery of the turbine impeller and having adischarge opening radially from the turbine impeller. The casing havinga suction entrance for the turbine stage opening laterally from thefirst pumping channel to the second pumping channel. A centrifugalimpeller fixed for rotation within the first channel and with the driveshaft and turbine impeller.

PAIENTEnncI 19 l97| SHEET 10F d PATENTEDum 19 mm SHEET 30F 4 E w 1 @w a:a a J T PATENTEDnm 19 Ian a SWW MN COMBINATION CENTRIFUGALTURBINE PUMPBACKGROUND OF THE INVENTION This invention relates to a liquid pump forhandling liquids at or near the boiling point, and more particularlyrelates to a combination centrifugal-turbine pump.

The problems in pumping a liquid at or near the boiling point arethoroughly discussed in U.S. Pat. No. 2,875,698, issued to L. C. Rothand assigned to the same assignee as this invention. In this patent, acombination centrifugal-turbine pump is disclosed, which has been foundto perform very satisfactorily. This invention is directed toimprovements over the combination centrifugal-turbine pump disclosed inthe above-identified Roth patent. The addition of a centrifugal stageprior to a turbine stage as disclosed in the Roth patent, has been foundto satisfactorily pump liquids at boiling point with suction heads of 1foot or less.

Accordingly, one object of this invention is to provide a new andimproved combination centrifugal-turbine pump having a higher volumecapacity with a given casing diameter than is possible with previousdesigns.

Another object of this invention is to provide a new and improvedcombination centrifugal-turbine pump capable of operating with lowerr.p.m. of the rotor to produce the same volume for a given casingdiameter than is possible with previous designs.

A further object of this invention is to provide a new and improvedcombination centrifugal-turbine pump having a more uniform radial loadbalance on the impeller shaft assembly.

Further objects and advantages of the invention will appear from thefollowing detailed description, taken in connection with theaccompanying drawing, which shows the construction and operation of anillustrative embodiment of the invention.

DESCRIPTION OF DRAWING For a better understanding of this invention,reference may be had to the accompanying drawing, in which:

FIG. I is a longitudinal sectional view illustrating acentrifugal-turbine pump embodying the principles of this invention;

FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1 andlooking in the direction of the arrows;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 1 andlooking in the direction of the arrows;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3 andlooking in the direction of the arrows;

FIG. 5 is a sectional view taken along the line 55 of FIG. I and lookingin the direction of the arrows;

FIG. 6 is a sectional view taken along the line 6--6 of FIG. 5 andlooking in the direction of the arrows, illustrating the main body ofthe pump casing;

FIG. 7 is a sectional view taken along the line 77 of FIG. 3 and lookingin the direction of the arrows;

FIG. 8 is a sectional view taken along the line 88 of FIG. 7 and lookingin the direction of the arrows;

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 7 andlooking in the direction of the arrows;

FIG. 10 is a sectional view taken along the line 10-10 of FIG. 8 andlooking in the direction of the arrows;

FIG. 11 is a sectional view taken along the line l1-lll of FIG. 2 andlooking in the direction of the arrows; and

FIG. 12 is a sectional view taken along the line 12-l2 of FIG. 3 andlooking in the direction of the arrows.

DESCRIPTION OF PREFERRED EMBODIMENT There is illustrated in FIG. I, acombination centrifugal-turbine pump having a case, generally designatedby the reference numeral 10, which is supported on a frame 12. A casehead 14 is secured to the main body 15 of case It) by means of aplurality of cap screws 16. Inboard cover is secured between main body15 and case extension 17 by means of cap screws 18.

A shaft 22 is rotatably supported in the case extension 17. Acentrifugal impeller 24 and a turbine impeller 26 are fixed to rotatewith the shaft 22 by keys or splines 28 and 30, respectively. The shaft22 is journaled for rotation in case extension 17 by means of anoutboard bearing 32 and an inboard bearing 34, which are lubricatedthrough grease fittings 36 and 38, respectively. An adjusting collar 39and lock collar 40 provide for positive adjustment of the shaft-impellerassembly.

An inner adjusting collar 41 is screwed into an inner housing cap 43 andis locked in position by a setscrew 45 and the split side of the housingcap 43. A spring 47 bears against the bearing outer race 49 of inboardbearing 34 to preload the shaft-impeller assembly toward the shaftextension end. A lip type seal 51 is used to protect the bearings fromdirt and liquids.

The turbine impeller 26 has vanes. or blades 42 opening from theopposite side and peripherally from the impeller which are operable in achannel 44. The turbine impeller 26 rotates between inner and outerliners 46 and 53 which cooperate with the opposite sides of the impeller26 to form sealing surfaces 48.

A shaft sleeve 50 surrounds the shaft 22 and abuts against the inboardend of the hub 52 of the turbine impeller 26. A stuffing box 56 isdisposed between the shaft 22 and the inboard cover 20.

To allow the use of various styles of seals and/or packing, a sleeve 58is placed between the impeller 26 and shaft shoulder and cooperates witha seal rotating unit, having a spring 60, to place the center of theshaft in tension and the sleeves impellers and spacers in compression.No gaskets are needed at the sleeve-shaft shoulder joint to seal, for anexcellent finish on both sleeve and shaft shoulders combined with highloading per square inch effectively stops leaks of liquids or gasses atthis joint. The seal shown is a balanced type of seal but any other typeof seal or packing may be used to suit the liquid and pumpingconditions.

An annular stationary bushing 70 is disposed within the case 110 andsurrounds the hub 72 of the centrifugal impeller 24 and an impellerspacer 74. The centrifugal impeller 24 is held on the end of the shaft22 by means of a nut 76. The stationary bushing 70 acts in conjunctionwith a ring 77, which is driven by pins 78 extending into the turbineimpeller 26 to prevent leakage of high-pressure liquid back into the lowpressure centrifugal case. An annular groove 69 cut into the l. D.bushing 70 is connected by a passageway 7I of outboard cover 103 to alow-pressure point in the turbine working channel about l5 from thesuction entrance to the turbine stage. This groove 69 bleeds off liquidwhich passes ring 77 and bushing 70 to a slightly pressurized part ofturbine stage where it will not have a detrimental effect on either theturbine or centrifugal stage. This sealing arrangement is described incomplete detail in U.S. Pat. No. 3,154,020, issued to Leonard J.Sieghartner, and having the same assignee as this invention.

Centrifugal impeller 24 has a one-piece housing 80 (FIGS. II and 7)having an inner annular rim portion 82, an intermediate flared skirtportion 84, and an outer annular rim portion 86. An inlet opening 88 isformed in the inner end of the housing 80 and is in direct communicationwith inlet opening 90 of case head 14. The inlet opening 90 is verylarge as compared with the overall diameter of impeller 24. The innerrim portion is rotatably supported by a bushing 92 seated in an annulargroove 94 at the outer end of cylindrical wall 96 which defines inletopening 90. At the outer end of housing 80 for impeller 24 is a circularwall 98 having a central hub 72.

Centrifugal impeller 24 has three equally spaced discharge openings 1M)(FIGS. 3, 4 and 7) which are formed in the peripheral surface of outerrim portion 86 of housing 80. These discharge openings 100 are in directcommunication with volute channel 102 extending generally angularlyabout and spaced outwardly from the periphery of the centrifugalimpeller 24.

The centrifugal impeller provided in the pump of this invention is of aspecial type having a very low-pressure creating characteristic and ahigher volumetric efficiency as compared with prior centrifugal impellerdesigns. A higher volumetric efficiency is possible by virtue of thedeep blades 104 (FIG. 3) having a particular design formed incentrifugal impeller 24. Blades 104 are in equal space relation aboutthe center of wall 98 and the axis of shaft 22 and have identicalshapes. Each blade 104 comprises an outer curved portion 106 extendingperpendicular from plate 98, having a constant axial width and an innercurved portion 108 gradually increasing in axial width from the centerof centrifugal impeller 24 in a diverging outward direction towards theopposite ends of the outer curved portion 106. The outer curved portion106 comprises a first arcuate segment 107 with an outer surfaceconcentric with the center of impeller 24, and a second arcuate segment109 extending inwardly from one end of the first arcuate segment 107 ashort distance so as to leave a space between its innermost end and thecenter of impeller 24. Thus the first arcuate segment 107 of the threeouter curved portions 106 form the outer annular rim portion 86 ofhousing 80 and the spacing between adjacent segments 107 definesdischarge outlets 100 for centrifugal impeller 24.

By virtue of the specially designed blades 104, the liquid enteringinlet 88 impinges against rotating circular plate 98 and is smoothlydirected outwardly along the inner curved portions 108 and outer curvedportions of blades 104 to the three discharge outlets 100 into volutechannel 102. The impeller blades 104 are arranged so that the liquid ismore restricted in leaving the discharge outlets 100 than the liquidentering through inlet 88 so that nowhere in impeller 24 is there a dropin pressure, but rather a steady increase in pressure with the leastpossible disturbance. The particular shape of blades 104, with the innercurved portion 108 tapering down to the center of impeller 24 aids theimpeller pressure buildup.

Volute channel 102 has a specially designed interior for guiding a largevolume of liquid at the boiling point from the three outlets 100 ofcentrifugal impeller 24 into the channel 44 of the turbine stage. Toprevent boiling of the liquid being pumped, it is essential that thevolute channel 102 be designed to avoid any disturbance being introducedto the liquid.

The volute channel 102 is formed in the case head and enclosed at itsouter end by main body 15 of case and outboard cover 103. A cavity 116is formed in case head 14 to define volute channel 102 and extendslaterally away from outboard cover 103 and discharge outlets 100 ofcentrifugal impeller 24. Extending generally perpendicular from wall 114of the cavity 116 are three equally spaced diffuser vanes 118 (FIGS. 2and 3). These vanes 118 have at their outer end 117 a generallyspherical cross section with a cutout 120 to accommodate the outer rimportion 86 of the centrifugal impeller 24. The base 119 of the threevanes 118 are supported on a slanting wall 122 which diverges outwardlyfrom the rear wall 114.

As illustrated in FIG. 2, the cavity 116 gradually increases in volumefrom its closed end 124 to its open end 126. At the open end 126 of thecavity 116, an inclined block 130is provided which extends forwardlyfrom the rear wall 114 of the cavity 116. The inclined block 130 directsthe liquid from the impeller stage forwardly to the entrance 131 tochannel 44 of the turbine stage. As illustrated in FIG. 11, the inclinedblock or guide ramp 130 for directing the liquid into the turbine stageextends at an obtuse angle away from the innermost wall 114 towards theouter end of the cavity 116 formed in the case head 14.

Diffuser vanes 118 provide an important function in the operation of thecentrifugal stage, for they serve to straighten the flow of liquidexiting from discharge outlets 100 of centrifugal impeller 24. By virtueof their close proximity to the outer rim portion 86 of impeller 24,diffuser vanes 118 also provide for multiple outlets for impeller 24resulting in a more uniform radial load balance on the impeller shaftassembly.

As illustrated in FIG. 3, the face 140 of main body in opposing relationwith the case head 14 has a shallow cavity 142 having an identicalcross-sectional shape to cavity 116 in case head 14. At the suctionentrance 131 to channel 146 of the turbine stage, a slightly incliningsurface 144 (FIG. 12) is provided which mates with inclined block (FIG.11) to guide the liquid into the turbine stage.

Channel 146, which is formed in the main body 15 of casing 10, providesa passageway for the liquid into liquid channel 44, which is formedabout the outer periphery of turbine impeller 26 between inner and outerliners 46 and 53.

A baffle 148 is placed across the suction of the turbine stage byforming the baffle 148 integral with the main body 15 (see FIG. 6) andin position extending across the inlet to channel 44. The particularbaffle 148 illustrated in the drawing is shown of tapered form, with itstapering sides 150 converging outwardly to a relatively sharp edge.Baffle 148 prevents the liquid thrown from turbine impeller 26 frominterfering with the incoming liquid.

Provided in body portion 15 of casing 10 is an outlet 154 (FIG. 6) forthe turbine stage which is in direct communication with liquid channel44. To prevent the pressurized liquid from escaping to the suction ofthe turbine stage, a pair of block members 156 (FIGS. 8 and 9) areintegrally formed with inner and outer liners 46 and 53 to interruptliquid channel 44. 1

In the operation of the pump, the liquid enters the suction entrance orinlet 88 of the centrifugal impeller 24 and is discharged throughoutlets 100 from the periphery of centrifugal impeller 24 into thevolute channel 102 at increased pressure and higher velocity. The liquiddischarged from outlets 100 impinges against vanes 118, which serve tostraighten the flow. The liquid is directed to the rear wall 114 ofcavity 118 in a swirling motion towards inclined block 130, where theliquid is guided towards suction entrance 131 of the turbine stage. Theliquid then passes through suction entrance 131 into the annular liquidchannel 44 of the turbine stage. The regenerative pumping action ofturbine impeller 26 builds up sufficient pressure to deliver the liquidto the outlet 154 of the turbine stage, by constant recirculation of theliquid through the impeller vanes 42 and annular channel 44.

I claim:

1. An improved centrifugal-turbine pump capable of pumping liquids andliquified gases at or near the boiling point thereof with suction headsnot greater than about I foot, having a pump casing with a first pumpingchannel and a second pumping channel disposed laterally of said firstpumping channel, a drive shaft disposed axially of said pumpingchannels, a high-pressure regenerative turbine impeller fixed forrotation with said driving shaft, said second pumping channel extendinggenerally angularly about and spaced outwardly from the periphery ofsaid turbine impeller and having a discharge opening generally radiallyfrom said turbine impeller, said casing having a suction entrance forthe turbine stage opening laterally from said first pumping channel tosaid second pumping channel, and a centrifugal impeller fixed forrotation within said first pumping channel and with said driving shaftand turbine impeller, said centrifugal impeller having a large diameteraxial inlet opening of substantially the same as a suction inlet for thecentrifugal stage defined by said casing, said centrifugal impellercomprising a plurality of equally spaced blades for said centrifugalimpeller inwardly from the periphery of said first pumping channel, eachof said blades having an outer curved portion of constant axial widthand an inner curved portion gradually increasing in axial width from thecenter of said centrifugal impeller in a diverging outward directiontowards the opposite ends of said outer curved portion, each of saidouter curved portion having a first arcuate segment concentric with saidcenter and a second arcuate extending inwardly from one end of saidfirst arcuate segment a short distance leaving a space between itsinnermost end and said center, where a plurality of equally spaceddischarge outlets for said centrifugal impeller is defined by openingsprovided between the adjacent ends of said first arcuate segments.

2. An improved centrifugal-turbine pump ofclaim 1, wherein saidcentrifugal impeller includes at least three of said blades.

3. An improved centrifugal-turbine as defined in claim ll, wherein saidfirst pumping channel is defined by a cavity in said casing extendinglaterally away from said turbine stage to a rear wall with the area ofsaid cavity annular about the periphery of said centrifugal impeller andincreasing in volume between a closed end and an open end, and anaxially inclined block in said cavity between said rear wall and saidsuction entrance for the turbine stage to guide the liquid into saidturbine stage.

4. An improved centrifugal-turbine as defined in claim 3, wherein saidfirst pumping channel further includes a plurality of spaced diffuservanes extending from said rear wall towards said turbine stage anddisposed in close proximity to said periphery of said centrifugalimpeller to straighten the flow of liquid exiting from said dischargeoutlets of said centrifugal impeller.

5. An improved centrifugal-turbine pump capable of pumping liquids andliquified gases at or near the boiling point thereof with suction headsnot greater than about 1 foot, having a pump casing with a first pumpingchannel and a second pumping channel disposed laterally of said firstpumping channel, a drive shaft disposed axially of said pumpingchannels, a high pressure regenerative turbine impeller fixed forrotation with said driving shaft, said second pumping channel extendinggenerally angularly about and spaced outwardly from the periphery ofsaid turbine impeller and having a discharge opening generally radiallyfrom said turbine impeller, said casing having a suction entrance forthe turbine stage opening laterally from said first pumping channel tosaid second pumping channel and a centrifugal impeller fixed forrotation within said first pumping channel and with said driving shaftand turbine impeller, said centrifugal impeller having a large diame'ter axial inlet opening of substantially the same as a suction inlet forthe centrifugal stage defined by said casing, said centrifugal impellercomprising a plurality of equally spaced blades for said centrifugalimpeller inwardly from the periphery of said first pumping channel, saidfirst pumping channel defined by a cavity formed in said casingextending laterally away from said turbine stage with the area of saidcavity annular about the periphery of said centrifugal impeller andincreasing in volume between a closed end and an open end, and anaxially inclined block in said cavity between said rear wall and saidsuction entrance for the turbine stage to guide the liquid into saidturbine stage.

6. An improved centrifugal-turbine as defined in claim 5, wherein saidfirst pumping channel further includes a plurality of spaced diffuservanes extending from said rear wall towards said turbine stage anddisposed in close proximity to said periphery of said centrifugalimpeller to straighten the flow of liquid exiting from said dischargeoutlets of said centrifugal impeller.

1. An improved centrifugal-turbine pump capable of pumping liquids andliquified gases at or near the boiling point thereof with suction headsnot greater than about 1 foot, having a pump casing with a first pumpingchannel and a second pumping channel disposed laterally of said firstpumping channel, a drive shaft disposed axially of said pumpingchannels, a high-pressure regenerative turbine impeller fixed forrotation with said driving shaft, said second pumping channel extendinggenerally angularly about and spaced outwardly from the periphery ofsaid turbine impeller and having a discharge opening generally radiallyfrom said turbine impeller, said casing having a suction entrance forthe turbine stage opening laterally from said first pumping channel tosaid second pumping channel, and a centrifugal impeller fixed forrotation within said first pumping channel and with said driving shaftand turbine impeller, said centrifugal impeller having a large diameteraxial inlet opening of substantially the same as a suction inlet for thecentrifugal stage defined by said casing, said centrifugal impellercomprising a plurality of equally spaced blades for said centrifugalimpeller inwardly from the periphery of said first pumping channel, eachof said blades having an outer curved portion of constant axial widthand an inner curved portion gradually increasing in axial width from thecenter of said centrifugal impeller in a diverging outward directiontowards the opposite ends of said outer curved portion, each of saidouter curved portion having a first arcuate segment concentric with saidcenter and a second arcuate extending inwardly from one end of saidfirst arcuate segment a short distance leaving a space between itsinnermost end and said center, where a plurality of equally spaceddischarge outlets for said centrifugal impeller is defined by openingsprovided between the adjacent ends of said first arcuate segments.
 2. Animproved centrifugal-turbine pump of claim 1, wherein said centrifugalimpeller includes at least three of said blades.
 3. An improvedcentrifugal-turbine as defined in claim 1, wherein said first pumpingchannel is defined by a cavity in said casing extending laterally awayfrom said turbine stage to a rear wall with the area of said cavityannular about the periphery of said centrifugal impeller and increasingin volume between a closed end and an open end, and an axially inclinedblock in said cavity between said rear wall and said suction entrancefor the turbine stage to guide the liquid into said turbine stage.
 4. Animproved centrifugal-turbine as defined in claim 3, wherein said firstpumping channel further includes a plurality of spaced diffuser vanesextending from said rear wall towards said turbine stage and disposed inclose proximity to said periphery of said centrifugal impeller tostraighten the flow of liquid exiting from said discharge outlets ofsaid centrifugal impeller.
 5. An improved centrifugal-turbine pumpcapable of pumping liquids and liquified gases at or near the boilingpoint thereof with suction heads not greater than about 1 foot, having apump casing with a first pumping channel and a second pumping channeldisposed laterally of said first pumping channel, a drive shaft disposedaxially of said pumping channels, a high pressure regenerative turbineimpeller fixed for rotation with said driving shaft, said second pumpingchannel extending generally angularly about and spaced outwardly fromthe periphery of said turbine impeller and having a discharge openinggenerally radially from said turbine impeller, said casing having asuction entrance for the turbine stage opening laterally from said firstpumping channel to said second pumping channel and a centrifugalimpeller fixed for rotation within said first pumping channel and withsaid driving shaft and turbine impeller, said centrifugal impellerhaving a large diametEr axial inlet opening of substantially the same asa suction inlet for the centrifugal stage defined by said casing, saidcentrifugal impeller comprising a plurality of equally spaced blades forsaid centrifugal impeller inwardly from the periphery of said firstpumping channel, said first pumping channel defined by a cavity formedin said casing extending laterally away from said turbine stage with thearea of said cavity annular about the periphery of said centrifugalimpeller and increasing in volume between a closed end and an open end,and an axially inclined block in said cavity between said rear wall andsaid suction entrance for the turbine stage to guide the liquid intosaid turbine stage.
 6. An improved centrifugal-turbine as defined inclaim 5, wherein said first pumping channel further includes a pluralityof spaced diffuser vanes extending from said rear wall towards saidturbine stage and disposed in close proximity to said periphery of saidcentrifugal impeller to straighten the flow of liquid exiting from saiddischarge outlets of said centrifugal impeller.